The government last night moved to claw back half of the £16m pension pot for the disgraced RBS chief executive, Sir Fred Goodwin, as it launched a wider review of the multi-million pound rewards earned by ousted executives of the bailed-out banks.

The move by ministers came as Goodwin was still refusing to relinquish his pension payout of £693,000 a year that he claims was secured with the knowledge of the City minister, Lord Myners.

In an attempt to defuse the embarrassing row over gold-plated pensions and benefits, the body set up to preside over the publicly owned banks revealed it had demanded a review of all payments to ousted HBOS directors.

The Guardian has revealed that the board of HBOS, which yesterday reported a £10.1bn loss for 2008, may have walked away with combined payments of up to £4.5m. None of the executives at HBOS were offered a place on the board of the merged group after Lloyds TSB rescued the collapsing bank.

Most of the focus last night was on Peter Cummings, the executive responsible for the HBOS division that caused huge losses. He is thought to have received one year's salary and benefits of £800,000 when he left the bank last month and started receiving his £350,000-a-year pension at the age of 53. Executives close to 55 are entitled to have their pensions topped up, which suggests that Cummings's £5.9m pension pot will have been enhanced.

In the bitter fight over Goodwin's pension, ministers also indicated that Treasury solicitors were working on a complex proposal to halve his pension pot to £8m by taking away the discretionary cash awarded by the RBS board before he stood down. "It will need to be done very delicately because it a legal nightmare," said one minister.

Myners came under pressure from the Tories and the unions yesterday to step down because of his handling of the crisis. Shadow chancellor George Osborne said Myners was in a very difficult position as he had known about the size of the pension last October and did not do anything about it. The senior Tory on the treasury select committee, Michael Fallon, called on Myners to resign.

John McFall, Labour chairman of the committee, said he felt "anger and frustration" over the size of Goodwin's pension. "Anger at the slap in the face for the taxpayer standing behind these banks and frustration at the lack of appreciation shown by executives in banks for why they are called gamblers with other people's money."

McFall's committee is taking evidence next Tuesday from UK Financial Investments, the body set up to look after £37bn of taxpayer stakes in RBS and Lloyds Banking Group. McFall said he would ask UKFI for more detail about Goodwin's deal. "First of all, in October who signed it off? Was it [former RBS chairman] Sir Tom McKillop and senior non-executive director Bob Scott only? Secondly, was it discretionary? Thirdly, how is it that this whole bank board signed this off in January? These are questions that need answering."

Gordon Brown, forced to support Myners, condemned the deal for his former adviser, Goodwin, while visiting Oxford. "I think the whole public know that when people make mistakes and banks fail, the people who made the mistakes can't and shouldn't run off with entitlements and with additional discretionary payments that people rightly believe they shouldn't have."

UKFI is now seeking clarity about rewards for departed HBOS executives. The decision to review the payouts to ensure they are in line with their legal entitlements was made last week at the same time as it started to review the payouts to Goodwin. UKFI revealed the inquiry only after Sir Victor Blank, chairman of Lloyds, said he would analyse any payments to the HBOS board if he was asked to to so.

UKFI said: "Lloyds agreed with UKFI last week that it would assure itself that all payouts to former HBOS directors were, as UKFI had previously been assured by HBOS, no more than legally necessary. We understand that this process of thorough legal assurance is nearly complete."

Negative equity soars

Halifax, the country's biggest mortgage lender, revealed the latest impact of the downturn yesterday by revealing one in six of its customers are in negative equity. As its parent company HBOS admitted it had dived to a £10.8bn loss in 2008, Halifax said 17% of its customers had loans larger than the value of their homes, compared with just 0.1% a year ago. Rescued by Lloyds TSB to form Lloyds Banking Group, HBOS's losses are making a huge dent in the enlarged group.